Deficient visual performance can have a significant negative impact on a patient's quality of life, affecting, for example, ability to perform normal daily tasks, perform at school, and perform at work. The inability to see clearly can impact people during normal daylight conditions and during low-light conditions, such as nighttime. One type of vision problem experienced by a substantial number of patients is poor night vision. The inability to see clearly under such low light conditions can make it difficult and/or dangerous for a patient to operate a motor vehicle at nighttime. Patients that are more likely to experience night vision problems include those suffering from night myopia, have an equatorial cortical cataract, have had surgery to insert an intraocular lens, and/or underwent LASIK surgery. Exemplary symptoms of poor night vision include glare, halos, starburst, ghosting patterns, and/or poor depth perception.
Certain therapies have been described for improving visual performance. For example, the Bernstein Center for Visual Performance offers programs that utilize visual aids, such as puzzles, stereoscopes, and eye glasses, designed to improve visual performance. U.S. Pat. No. 6,291,498 describes the use of phentolamine to, for example, optimize pupil size in a patient. However, one adverse side effect of phentolamine administered to the eye of a patient is eye redness. The need exists for methods and compositions that provide the patient with improved visual performance during the patient's waking hours, while minimizing the occurrence and/or degree of eye redness caused by phentolamine during the patient's waking hours.
The present invention addresses the aforementioned need for methods and compositions for achieving improved visual performance while minimizing the occurrence and/or degree of eye redness caused by phentolamine during the patient's waking hours, and the invention provides other related advantages.